Cubic phase, nitrogen-based compound semiconductor films

Abstract

A method of epitaxially growing nitrogen-based compound semiconductor thin films on a semiconductor substrate, which is periodically patterned with grooves. The method can provide an epitaxial growth of a first crystalline phase epitaxial film on the substrate, and block the growth of an initial crystalline phase with barrier materials prepared at the sides of the grooves. Semiconductor devices employing the epitaxial films are also disclosed.

What is claimed is:  
     
       1. A method of forming a semiconductor device, comprising:
 forming a plurality of grooves within a semiconductor substrate; 
 forming a mask structure comprising a plurality of openings therein over the semiconductor substrate wherein the plurality of openings are aligned with the plurality of grooves; 
 growing a nitrogen-based compound semiconductor epitaxial layer from each of the plurality of grooves in the semiconductor substrate, the epitaxial layer comprising a first crystal phase and a second crystal phase; and 
 blocking the first crystal phase material with the sidewalls of the mask structure, wherein at least a portion of the second crystal phase material grows through each of the plurality of openings in the mask structure. 
 
     
     
       2. The method of  claim 1 , wherein the first crystal phase is a hexagonal phase and the second crystal phase is a cubic phase. 
     
     
       3. The method of  claim 1 , wherein the second crystal phase material is coalesced to form a wide area film. 
     
     
       4. The method of  claim 1 , wherein the second crystal phase material forms a plurality of island films. 
     
     
       5. The method of  claim 1 , wherein forming a plurality of grooves further comprises:
 providing a mask on a surface of the (001) semiconductor substrate; and 
 etching the semiconductor substrate to form a plurality of grooves, each wall of the plurality of grooves revealing opposing {111} crystal planes of the semiconductor substrate. 
 
     
     
       6. The method of  claim 5 , wherein the etching comprises:
 anisotropically etching the (001) semiconductor substrate to expose the {111} crystal planes. 
 
     
     
       7. The method of  claim 5 , wherein the (001) semiconductor substrate is one of silicon, germanium, or a III-V material. 
     
     
       8. The method of  claim 1 , wherein the mask structure is formed from a single material. 
     
     
       9. The method of  claim 1 , wherein the shape of the groove causes a transformation from the second crystal phase to the first crystal phase during epitaxial growth. 
     
     
       10. A method of forming a semiconductor device, comprising:
 forming a plurality of grooves within a semiconductor substrate; 
 forming a mask structure comprising a plurality of openings therein over the semiconductor substrate wherein the plurality of opening are aligned with the plurality of grooves; 
 growing an epitaxial layer from each of the plurality of grooves in the semiconductor substrate, wherein the epitaxial layer comprises hexagonal phase material and cubic phase material; 
 blocking growth of the hexagonal phase material with a portion of the mask structure, wherein the cubic phase material grows through each of the plurality of openings in the mask structure; 
 stopping the growth of the cubic phase material; 
 forming a planarization material over an upper surface of the cubic phase material; 
 removing a portion of the planarization material; 
 forming a mask having openings over the planarization material, wherein the openings are spaced a lateral distance from each of the plurality of grooves; 
 etching the planarization material through the mask openings to form a space between a surface of the mask structure and the mask; 
 further growing the cubic phase material to at least partially fill the space between the first mask layer and the second mask layer; and 
 removing the second mask layer to expose the cubic phase material. 
 
     
     
       11. The method of  claim 10 , wherein the exposed cubic phase material is coalesced to form a wide area film. 
     
     
       12. The method of  claim 10 , wherein the exposed cubic phase material forms a plurality of island films. 
     
     
       13. The method of  claim 10 , wherein forming a plurality of grooves further comprises:
 providing a mask aligned on a (001) surface of the semiconductor substrate; and 
 etching the semiconductor substrate to form a plurality of grooves, each wall of the plurality of grooves revealing opposing {111} crystal planes of the semiconductor substrate. 
 
     
     
       14. The method of  claim 13 , wherein the etching comprises:
 anisotropically etching the silicon substrate to expose the {111} crystal planes. 
 
     
     
       15. The method of  claim 14 , wherein the growth of the hexagonal phase material is blocked such that only the cubic phase material grows above the mask structure. 
     
     
       16. A method of forming a semiconductor device, comprising:
 forming a plurality of grooves within a semiconductor substrate; 
 forming a mask structure comprising a plurality of openings therein over the semiconductor substrate wherein the plurality of opening are aligned with the plurality of grooves; 
 growing an epitaxial layer from each of the plurality of grooves in the semiconductor substrate, wherein the epitaxial layer comprises hexagonal phase material and cubic phase material; 
 blocking growth of the hexagonal phase material with a portion of the mask structure, wherein the cubic phase material grows through each of the plurality of openings in the mask structure; and 
 covering an upper surface of the mask layer with lateral growth of the cubic phase material, wherein the crystal growth is stopped before complete coalescence so as to form a plurality of island films. 
 
     
     
       17. The method of  claim 16 , wherein the mask structure is formed from a single material comprising sidewalls with a thickness sufficient to block the growth of the hexagonal phase materials.